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AC impedance spectroscopy of a-nc-Si:H Thin Films

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Engineering（科研） 2014年第8期6卷 449-461页

作者： Vladimir Tudic Department of Mechanical Engineering & Mechatronics Karlovac University of Applied Sciences Karlovac Croatia

The AC impedance of amorphous-nano-crystalline silicon composite thin films (a-nc-Si:H) from mHz to MHz at different temperatures has been studied. The samples were prepared by Plasma Enhanced Chemical Vapor Deposition technique. The X-ray diffraction and high resolution electron microscopy showed that films consist of isolated nano-crystals embedded in amorphous matrix. In analysis of impedance data, two approaches were tested: the ideal Deby type equivalent circuit and modified one, with CPE (constant phase elements). It was found that the later better fits to results. The amorphous matrix showed larger resistance and lower capacity than nano-crystals. By heat treatment in vacuum, the capacity for both phases changes, according to expected change in size of ordered domains.

关键词： a-nc-Si:H impedance spectroscopy Composite Thin Film Equivalent Circuit

Noninvasive Measurement of Blood Glucose by Dynamic Pulse impedance spectroscopy

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Noninvasive Measurement of Blood Glucose by Dynamic Pulse Im...

Dielectric,impedance,modulus spectroscopy and AC conductivity studies on novel organic ferroelectric diisopropylammonium chloride(dipaCl)

第三届国际仪器科学技术学术研讨会

作者： LI Gang LU Zong-wu LIN Ling State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University Tianjin 300072 China

Noninvasive blood glucose measurement by impedance will certainly be well developed because of its easy use, low cost, high sensitivity and very short measuring time. However, it is difficult to impro

关键词： Pulse Wave impedance spectroscopy Blood Glucose Noninvasive Measurement

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Journal of Advanced Dielectrics 2021年第4期11卷 18-26页

作者： Mamataj Khatun Ekramul Kabir Department of Physics Aliah UniversityNewtown Campus Kolkata 700160India Department of Physics Darjeeling Govt.College Darjeeling 734101India

Organic molecular ferroelectric diisopropylammonium chloride(dipaCl)was successfully synthesized using diisopropylamine,hydrochloric acid(57%)and methanol *** permittivity,impedance,modulus spectroscopy and conductivity were systematically studied by Capacitance-Conductance(CP-G)measurements in the temperature range of 373-445 *** property tests clearly show that the organic molecular ferroelectric dipaCl obeys Curies-Weiss law 1/e=(T-T0)/*** real(Z′)and imaginary(Z″)parts of the electrical modulus were calculated from the various values of e′and e″.It is shown that AC conductivity satisfies the relation s(w)∞wn,where the power exponent n depends on temperature and *** Arrhenius equation,the activation energies Es and Eh are also calculated which describes the complete conduction mechanism of dipaCl.

关键词： Molecular ferroelectrics dielectric spectroscopy impedance spectroscopy conductivity

Magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

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Journal of Rare Earths 2024年第2期42卷 373-382,I0005页

作者： N.M.Basfer Hanaa Almaghamsi Department of Physics Umm AL-Qura UniversityMakkahSaudi Arabia Physics Department College of Science and ArtKing Abdulaziz UniversityPOB344Rabigh291Saudi Arabi

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)Mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CMCF) ferrite nanoparticles were investigated in *** magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ***,coercivity increases from 738.22 Gs for the CMCFO sample to 912.10 Gs for the CMCF2 sample,then decreases monotonically to 762.1 Gs for the CMCF5 *** cerium content and particle size play important roles in controlling the magnetization and coercivity of the CMCF *** CMCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 *** CMCF nanoferrites' dielectric parameter dispersion exhibits normal *** pristine Co-Mg nanoferrite only has ε' value of 28.25,but the nanoferrite MCMF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the MCMF nanoferrites was determined by fitting the σ_(ac) results via the Jonscher power *** 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher ***-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher *** on our results,the CMCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

关键词： Nanoferrites Rare earth ions Magnetic properties Dielectric parameters impedance spectroscopy

The circuitry landscape of perovskite solar cells:An in-depth analysis

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Journal of Energy Chemistry 2024年第7期94卷 393-413页

作者： Siddhi Vinayak Pandey Daniel Prochowicz Apurba Mahapatra Saravanan Pandiaraj Abdullah N.Alodhayb Seckin Akin Pankaj Yadav Department of Solar Energy School of Energy TechnologyPandit Deendayal Energy UniversityGandhinagar 382007GujaratIndia Department of Physical Chemistry Polish Academy of SciencesKasprzaka 44/5201-224 WarsawPoland Department of Self-Development Skills King Saud UniversityRiyadh 11451Saudi Arabia Department of Physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Department of Metallurgical and Materials Engineering Necmettin Erbakan University42060 KonyaTurkey Department of Physics School of Energy TechnologyPandit Deendayal Energy UniversityGandhinagar 382007GujaratIndia

The extensive research and development in perovskite solar cells (PSCs) have rekindled the hopes of converting solar energy into *** elusive understanding of underlying mechanisms is required for the development of efficient *** the years,impedance spectroscopy (IS) characterization,along with complementary techniques,has proven to be an effective way to understand and analyze the charge transport and recombination at interface and bulk of *** IS of PSCs have been analyzed,interpreted,and improvised continuously,revealing intricate details about the ***,there is a lack of centralized source of these details,which make it tougher to account for the generalized approach to understand the device *** present work is focused on compiling the research done on various PSC device architectures via IS to construct a comprehensive foundation of information on impedance plots,equivalent circuits,and associated processes.

关键词： impedance spectroscopy Perovskite solar cells Equivalent Circuits

Electrical transport in lead-free Na_(0.5_Bi_(0.5)TiO_(3) ceramics

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Journal of Advanced Ceramics 2021年第1期10卷 152-165页

作者： J.SUCHANICZ K.KLUCZEWSKA-CHMIELARZ D.SITKO G.JAGLO Institute of Technology Pedagogical Universityul.Podchorazych 230-084 KrakowPoland Institute of Physics Pedagogical Universityul.Podchorazych 230-084 KrakowPoland

Lead-free Na_(0.5_Bi_(0.5)TiO_(3) (NBT)ceramics were prepared via a conventional oxide-mixed sintering route and their electrical transport properties were *** current(DC,σDC)and alternating current(AC,σAc)electrical conductivity values,polarization current(first measurements)and depolarization current,current-voltage(I-U)characteristics(first measurements),and the Seebeck coefficient(a)were determined under various *** mechanism of depolarization and the electrical conductivity phenomena observed for the investigated samples were found to be *** low voltages,the I-U characteristics were in good agreement with Ohm^law;for higher voltages,the observed dependences were I-U^(2),1-U^(4),and then I-U^(6).The low-frequencyσAC followed the formulaσAC-ω^(s)(ωis the angular frequency and 5 is the frequency exponent).The exponent s was equal to 0.18-0.77 and 0.73-0.99 in the low-and high-frequency regions,respectively,and decreased with temperature *** was shown that conduction mechanisms involved the hopping of charge carriers at low temperatures,small polarons at intermediate temperatures,and oxygen vacancies at high *** on AC conductivity data,the density of states at the Fermi-level,and the minimum hopping length were *** conduction was found to undergo p-n-p transitions with increasing *** transitions occurred at depolarization temperature 7d,280℃,and temperature of the maximum of electric permittivity Tm is as typical of NBT materials.

关键词： Na05Bi05TiO3(NBT)ceramics electrical properties Seebeck coefficient impedance spectroscopy

Structural and electrical properties of La_(2-x)Sr_xMo_2O_(9-δ)

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Journal of Rare Earths 2013年第4期31卷 428-434页

作者：闫柏军李明张家芸 State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological EngineeringUniversity of Science and Technology Beijing

Sr-doped La2Mo2O9 were prepared by solid state reaction and characterized by XRD, impedance spectroscopy and Hebb- Wagner polarization method. XRD patterns of the samples indicated that the solubility limit of Sr2＋ in La2-xSrxM02O9 -δ was in the range of 7 mol.% to 7.5 tool.%, i.e., the maximum stoichiometric coefficient x in La2~SrxMo209_a was larger than 0.14 and less than 0.15. The cubic lattice parameter of La2 xSrxM02Og-δ （0〈x〈4） increased linearly with the content of dopant Sr2＋ increasing and the relationship could be expressed as： a=0.7154＋0.0045 lx （ram）. The total conductivities of Sr-doped La2M0209 were measured by im- pedance spectroscopy method in argon and air atmosphere, respectively. The results indicated that substituting Sr2＋ fbr La3＋ could suppress the first order phase transform ofLa2M02O9 and stabilize the cubic structure to room temperature, and tile conductivities of Sr-doped La2M02O9 were more sensitive to the change of atmosphere than that of undoped La2M02O9. The conductivity variation of Sr-doped La2M02O9 with the dopant content exhibited similar trend in air and argon atmosphere, firstly decreased and then increased with the dopant content increasing, and a minimum value appeared at x=0.1. The electronic conductivities of Sr-doped La2M02O9 were measured using Hebb-Wagner polarization method in argon atmosphere. It could be found that Sr-doping caused the increase in electronic conductivity and decrease in oxide-ion transport numbers, but the conducting species were predominantly oxide ions. And the oxide-ion transport numbers of some St-doped La2Mo2O9 samples could also reach 0.99.

关键词： inorganic compounds ionic conduction X-ray diffraction impedance spectroscopy rare earths

Electrical Properties of NASICON-type Structured Li1.3Al0.3Ti1.7（PO4）3 Solid Electrolyte Prepared by 1,2-Propylene glycol-assisted Sol-gel Method

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Chinese Journal of Chemical Physics 2012年第6期25卷 703-707,I0004页

作者： Lin-chaoZhang Peng Chen Zhang Hu Chun-hua Chen CAS Key Laboratory of Materials for Energy Conversion Department of Materials Science. and EnEi-neering University of Science and Technology of China Hefei 230025 China

Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.

关键词： Lithium aluminum titanium phosphate Lithium-ion conductor NASICONelectrolyte impedance spectroscopy

Performance of Pr_(2)(Ni,Cu)O_(4+δ) electrodes in protonic ceramic electrochemical cells with unseparated and separated gas spaces

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Journal of Materials Science & Technology 2021年第34期93卷 157-168页

作者： Artem P.Tarutin Yulia G.Lyagaeva Aleksey I.Vylkov Maxim Yu.Gorshkov Gennady K.Vdovin Dmitry A.Medvedev Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes Institute of High Temperature ElectrochemistryYekaterinburg 620137Russia Ural Federal University Yekaterinburg 620002Russia

The Ln_(2)NiO_(4+δ)-based layered phases have attracted much attention as components for high-performance protonic ceramic fuel cells(PCFCs)and electrolysis cells(PCECs)enabling energy conversion with good efficiency and low *** present paper aims at rationally engineering the Cu-doped Pr_(2)NiO_(4+δ)materials and analysing their electrode behaviour for reversible protonic ceramic cells operating in both PCFC and PCEC *** oxides of Pr_(2)Ni_(1-x)CuxO_(4+δ)(x=0,0.1,0.2 and 0.3)were synthesised using the citrate-nitrate *** obtained materials were characterised considering their crystalline structures,as well as thermal,thermomechanical and electrotransport properties.A special interest was focused on the quality of an electrode/electrolyte interface governing the electrochemical performance of the cells *** is shown that a copper doping of x=0.2 has a positive impact on the thermomechanical compatibility of the Ba(Ce,Zr)O_(3)-based electrolytes,providing a better adhesion to these electrolytes at low-temperature sintering and resulting in a decrease of the polarisation resistance of the air electrodes.A reversible protonic ceramic cell demonstrates a power density of~340 m W cm^(-2) and a hydrogen output flux of~3.8 ml cm^(-2) min^(-1) at 750℃.The presented results propose modernised alkaline-earth-element-free and cobalt-free electrodes that can be successfully used in the electrochemical cells based on the-state-of-the-art proton-conducting electrolytes.

关键词： rSOC Proton conductivity Cathode Cu-doping Thermal expansion impedance spectroscopy